relative formula masses and molar volumes of gases
In this section you will be assessed on your ability to
1.16 calculate relative formula masses (Mr) from relative atomic masses (Ar)
1.17 understand the use of the term mole to represent the amount of substance 1.18 understand the term mole as the Avogadro number of particles (atoms,molecules, formulae, ions or electrons) in a substance
1.19 carry out mole calculations using relative atomic mass(Ar) and relative formula mass (Mr) 1.20 understand the term molar volume of a gas and use its values (24 dm3 and 24,000 cm3) at room temperature and pressure (rtp) in calculations
The mass of a compound compared to the mass of a C-12 atom (the most abundant carbon isotope) and is calculated by adding the relative atomic mass, multiplied by the number of atoms, of the elements in the compound.
on page 48 answer questions 1 to 5, 21 to 30 and 41 to 50
Calculating moles and masses
The molar mass of a substance is the mass of 1 mole of that substance which is the relative mass of the substance expressed in grams.
Calculating moles using mass: find the formula on page 2 of 1d handout or on the worksheet attached below.
Go to http://www.echalk.co.uk/ (remember username is echalk2@dulwich-shanghai.cn; password is echalk) and go to section "Chemical formulae, equations and calculations" and "introducing the mole": do both activities to practice calculating moles.
You can also calculate the number of moles easily of a gas because 1 mole of a gas is always 24 dm3 or L, for any gas. See handout 1d. Answer the questions at the bottom of page 2 of handout 1d.
Calculating molar volumes and masses
You will be asked to convert mass of a gas into a volume. This cannot be done directly so 'moles' will be the link. On the worksheet below answer questions 1, 2, 3 and 4.
relative formula masses and molar volumes of gases
In this section you will be assessed on your ability to
1.16 calculate relative formula masses (Mr) from relative atomic masses (Ar)1.17 understand the use of the term mole to represent the amount of substance
1.18 understand the term mole as the Avogadro number of particles (atoms,molecules, formulae, ions or electrons) in a substance
1.19 carry out mole calculations using relative atomic mass(Ar) and relative formula mass (Mr)
1.20 understand the term molar volume of a gas and use its values (24 dm3 and 24,000 cm3) at room temperature and pressure (rtp) in calculations
Section notes
Investigations
Resources
Textbook pages
Tutorials
Calculating moles, masses and number of particlesKey mole concepts
Lesson
MoleUsed to measure the amount of a chemical.
TED presentation on mole
Relative formula mass:
The mass of a compound compared to the mass of a C-12 atom (the most abundant carbon isotope) and is calculated by adding the relative atomic mass, multiplied by the number of atoms, of the elements in the compound.Calculating moles and masses
The molar mass of a substance is the mass of 1 mole of that substance which is the relative mass of the substance expressed in grams.Calculating moles and molar volumes
You can also calculate the number of moles easily of a gas because 1 mole of a gas is always 24 dm3 or L, for any gas. See handout 1d. Answer the questions at the bottom of page 2 of handout 1d.Calculating molar volumes and masses
You will be asked to convert mass of a gas into a volume. This cannot be done directly so 'moles' will be the link.On the worksheet below answer questions 1, 2, 3 and 4.